In the past, intravenous pole clamps have had no need for a locking feature. Security against theft or tampering was not considered to be a significant design consideration. Therefore, medical devices such as a pump simply contained a clamping mechanism, typically a screw thread/knob/bracket arrangement, for attaching to a pole. As new therapies have developed, such as patient controlled analgesia which uses narcotic analgesics, the need for increased security has arisen.
Some prior art patents disclosing I-V pole clamps include Design Pat. No. 269,156 (Slinkard) which discloses an I-V pole clamp with conventional means for securing to an I-V pole. U.S. Pat. No. 4,586,691 (Koslow) discloses a clamp for regulating the flow from an I-V bottle tube. U.S. Pat. No. 4,572,536 (Doughty) discloses a device for coupling an I-V pole to a wheelchair.
Other I-V pole clamps used in the field include those in which the medical device such as a pump is permanently affixed to the pole. It can only be removed by partially disassembling of the pole or the pump. User versatility and convenience is not available with this type system. Other contemporary systems include an I-V pole clamp that locks to a pole but uses a rachet mechanism rather than a spring clutch. With such a system, the knob used to tighten the mechanism to the pole can be rotated backwards up to one "ratchet tooth". This may result in loosening or even removal from certain poles. In such systems the pole mounting mechanism is permanently part of the pump. With such a system, not only must the user properly position the pole clamp, but the large, heavy pump must be simultaneously aligned and supported. Further, during transport of the medical device, the pole mounting mechanism must be carried as well.
Spring clutches are a design element which have been used for a number of applications in the past. U.S. Pat. No. 4,321,992 (Gallo) relates to a wrap spring clutch coupling. However, the Gallo clutch is directed to coupling two hubs and does not disclose either the clutch element of the present invention or application to an I-V pole clamp.